Two U.S. lawmakers who have been key critics of China say computers in their congressional offices suffered cyber attacks, apparently originating from China, compromising sensitive information. VOA's Dan Robinson has more on the story from Capitol Hill.

The electronic intrusions occurred on four computers used by staff of Congressman Frank Wolf, and on one used by staff of fellow Republican Chris Smith, both leaders on the issue of human rights in China, Vietnam and other nations.

Congressman Wolf told a news conference that computers used by his key foreign policy and human rights staffer, his chief of staff, legislative director, and a judiciary staff member were hacked:

"On these computers was information about all the case work I have done on behalf of political dissidents and human rights activists around the world," said Congressman Wolf. "That kind of information as well as everything else on my office computers, emails, memos, correspondence, district case work, was open to outside eyes."

Files on the computers were copied, but not deleted. Wolf says subsequent meetings with information staff and the F.B.I. revealed that the cyber-attacks emanated from a source within China, adding he was likely targeted because of his history of speaking out about China's abysmal human rights record.

Computers were also attacked at the same time in the House Africa, Global Human Rights and International Organizations Subcommittee, once chaired by Representative Smith.

"We had many names of dissidents and others on those computers, so while these may not be top secret types of things, when you have a dissident's name, when you have information concerning his or her whereabouts, what they are doing in China on behalf of human rights, when they go in and through an act of theft take that information, that is a very, very serious situation," said Congressman Smith.

Smith and Wolf acknowledge it is possible that a Chinese IP (Internet Protocol) address could have been faked by another source outside of China.

However, Wolf describes the operation as sophisticated, while Smith notes that the intrusion on his computer, which took the forum of a virus, was specifically aimed at files on China.

Saying he knows that computers of several other lawmakers were compromised, Wolf says he was urged by some groups, which he declined to identify, not to talk about the cyber attack and the information that was compromised.

But he says he decided to go ahead because of the importance of the issue. Pressed on the extent to which individuals were compromised by the attack or placed in jeopardy, Wolf had this response:

"Yes, they [China] have sent public security police to an individual in Fairfax County [Virginia]," he said. "They photographed her house. She was wise enough to get their license plate. I had the FBI run the license plate, and yes they were Chinese officials in Fairfax County."

Pete Hoekstra a former Republican chairman of the House Intelligence Committee, says the incidents underline the need for members of Congress to be aware of the threats to their own and the nation's information security:

"One of the countries, or one of the areas that is most active in this new world of exploitation through the Internet through electronic communication are the Chinese, the area of China, that part of the world is very, very active in this," said Congressman Hoekstra.

The FBI declined immediate comment on the matter Wednesday, citing national security concerns.

In a resolution he introduced in the House, Wolf urged that all members of Congress be briefed in a closed session by the FBI and homeland security officials on threats from China and other countries against computers and information systems.